PIER | |

Progress In Electromagnetics Research | ISSN: 1070-4698, E-ISSN: 1559-8985 |

Home > Vol. 54 > pp. 179-198
## RECONSTRUCTION OF EQUIVALENT CURRENTS USING A NEAR-FIELD DATA TRANSFORMATION - WITH RADOME APPLICATIONSBy K. Persson and M. Gustafsson
Abstract:
Knowledge of the current distribution on a radome can be used to improve radome design, detect manufacturing errors, and to verify numerical simulations. In this paper, the transformation from near-field data to its equivalent current distribution on a surface of arbitrary material, i.e., the radome, is analyzed. The transformation is based on the scalar surface integral representation that relates the equivalent currents to the near-field data. The presence of axial symmetry enables usage of the fast Fourier transform (FFT) to reduce the computational complexity. Furthermore, the problem is regularized using the singular value decomposition (SVD). Both synthetic and measured data are used to verify the method. The quantity of data is large since the height of the radome corresponds to 29-43 wavelengths in the frequency interval 8.0-12.0 GHz. It is shown that the method gives an accurate description of the field radiated from an antenna, on a surface enclosing it. Moreover, disturbances introduced by copper plates attached to the radome surface, not localized in the measured near field, are focused and detectable in the equivalent currents.
2. Yaghjian, A. D., "An overview of near-field antenna measurements," 3. Rahmat-Samii, Y., L. I. Williams, and R. G. Yaccarino, "The UCLA bi-polar planar-near-field antenna-measurement and diagnostics range," 4. Hanfling, J., G. Borgiotti, and L. Kaplan, "The backward transform of the near field for reconstruction of aperture fields," 5. Corey, L. E. and E. B. Joy, "On computation of electromagnetic fields on planar surfaces from fields specified on nearby surfaces," 6. Lee, J. J., E. M. Ferren, D. P. Woollen, and K. M. Lee, "Near-field probe used as a diagnostic tool to locate defective elements in an array antenna," 7. Varadan, V. V., Y. Ma, V. K. Varadan, and A. Lakhtakia, "Scattering of waves by spheres and cylinders," 8. Woodworth, M. B. and A. D. Yaghjian, "Derivation, application and conjugate gradient solution of dual-surface integral equations for three-dimensional, multi-wavelength perfect conductors," 9. Sarkar, T. K. and A. Taaghol, "Near-field to near/far-field transformation for arbitrary near-field geometry utilizing an equivalent electric current and MoM," 10. Ström, S., "Introduction to integral representations and integral equations for time-harmonic acoustic, electromagnetic and elastodynamic wave fields," 11. Balanis, C. A., 12. Jones, D. S., 13. Strang, G., 14. Kress, R., 15. Anton, H., 16. Jackson, J. D., |

© Copyright 2014 EMW Publishing. All Rights Reserved